1. Field of the Invention
The present invention relates to an X-ray diagnosis apparatus and an image processing apparatus
2. Description of the Related Art
Conventionally, a smoothing filter such as a recursive filter that performs a smoothing process between a plurality of frames in a time sequence is widely used as a method for reducing noise in an X-ray image.
Specifically, the recursive filter is a filter that reduces high frequency noise by adding pixel values of pixels constituting a past frame on which a predetermined weighting is performed to pixel values of pixels constituting a frame as a process target (for example, see JP-A 2007-330522 (KOKAI)).
Moreover, recently, in an intravascular interventional treatment that is widespread as a treatment method for an infarct site, a treatment using a stent is performed by a doctor who sees an X-ray image. However, in the intravascular interventional treatment, the treatment time may be long, so that an X-ray image (fluoroscopic image) is radiographed with the minimum X-ray dose to be radiated to a patient. Therefore, noise increases on an X-ray image to be seen by a doctor. Thus, reduction of noise on a fluoroscopic image by the smoothing filter is important in the intravascular interventional treatment.
The above described conventional technology has a problem in that the noise reducing effect by the smoothing filter is not always ensured.
In other words, when the recursive filter is applied to an X-ray image of an organ such as a heart that beats, which is radiographed in a time sequence, a target object to be filtered moves between a plurality of frames, so that motion blur occurs. Specially, in the intravascular interventional treatment for an infarct site of a heart, if the above described filter is applied, motion blur of a stent occurs in a fluoroscopic image by heartbeats.
In this manner, the recursive filter cannot be applied strongly to an X-ray image radiographed a moving object, so that noise cannot be reduced significantly.
The present invention has been achieved to solve the problem in the above conventional technology, and it is an object of the present invention to provide an X-ray diagnosis apparatus and an image processing apparatus capable of always ensuring a noise reducing effect by a smoothing filter.